A Precerebellin-like Protein is Part of the Acute Phase Response in Rainbow Trout, Oncorhynchus Mykiss

The acute phase response (APR) has a long evolutionary history, but it remains to be characterized fully in lower vertebrates. To study the acute phase proteins of a teleost, rainbow trout (Oncorhynchus mykiss), we induced an APR by injecting Vibrio bacterin emulsified in FIA. In samples taken over the next 3 weeks, the total plasma protein profile changed consistently as seen in one and two-dimensional SDS PAGE. One 18.1 kD upregulated protein was isolated from 2D gels and an N-terminal sequence obtained. Using reverse transcriptase-PCR, a 700 bp cDNA sequence was amplified. The sequence is 53% similar at the amino acid level with rat precerebellin (regions aa 42-184 from trout and aa 89-224 precerebellin), and 46% similar with the globular portion of the human B chain of the first complement component C1q. However, it lacks the collagen portion of C1q with its characteristic Gly-X-Y repeats. The isolated protein seems to be involved in the inflammatory response but its physiological function is unknown.